Nice rooms, bar at the pool is nice. However there...

Nice rooms, bar at the pool is nice. However there's something to lead me to believe that some hotel workers enter your room while you are away. Probably nothing but after house keeping had come by we stopped off in our room, relaxed and placed some money on a nightstand, a tip for the next days cleaners. We stepped out for an hour and when we came back the money was gone; nothing else was taken or added however, but still a little unsettling.